It is known that vehicle remote keyless entry systems (RKE) or passive keyless entry systems (PKE) can be susceptible to attacks referred to as a relay attack theft. Such a scenario known from the state of the art is shown in FIG. 1.
The keyless entry system for a vehicle 1 comprises a low frequency (LF) base station 2 and a radio frequency (RF) receiver 3 in the vehicle 1.
Further, the system comprises a security token 4, for example a key fob having an LF receiver 5 and an RF transmitter 6.
Under normal circumstance, when a user carrying the security token 4 approaches his vehicle 1 and lifts the door handle, the door handle will initiate the low frequency base station 2 to create a LF field with specific information. The LF field causes the LF receiver 5 of the security token 4 to power on and receive the information from the base station 2 via the LF field.
The information or a suitable response to the information is transmitted by the RF transmitter 6 as a message to the RF receiver 3 in the vehicle 1. After a verification of the message, i.e. the information or the response, access is granted and the vehicle is unlocked.
As shown in FIG. 1, a relay attack with two thieves T1, T2 may be carried out. Both thieves T1, T2 have LF/RF devices 7, 8 that communicate with each other.
The first thief T1 is close to the vehicle 1 and the second thief T2 is close to the user U of the vehicle.
The first thief T1 approaches the vehicle 1 and lifts the door handle to initiate the usual entry procedure. The LF/RF device 7 of the first thief T1 receives the information transmitted from the LF base station 2 in the LF field and sends this message to the corresponding LF/RF device 8 of the second thief T2.
The LF/RF device 8 of the second thief T2 in turn generates the same LF field with the same information as the vehicle 1 but close to the user U so that the security token 4 of the user U performs the same steps as if it were close to the vehicle 1.
The second thief T2 with its LF/RF device 8 receives the RF information or response transmitted from the RF transmitter 6 of the security token 4 and relays this information back to the LF/RF device 7 of the first thief T1.
The LF/RF device 7 of the first thief T1 then sends the same RF information or response to the RF receiver 3 of the vehicle 1.
For the vehicle 1, it seems that the security token 4 is within the vicinity of the vehicle 1 and thus the vehicle is unlocked even though the user U is far away from the vehicle 1.
Thus, there is a need to provide a method and a system for controlling access to a vehicle that prevent a relay attack on a vehicle without limiting the comfort of the keyless entry system.